I have 26 duck eggs in my incubator, but I had to start lockdown 2 days early because a lot of them have already internally pipped. There are 3 different breeds in the bator (Ancona, Rouen, and Cayuga). The Rouens always hatch first. With 3 different breeds, they usually hatch over a 4 day span. Anyway, I noticed when I put them on lockdown that some of the air sacs are very large whereas others are very small. This occurred in all 3 breeds. What do you do when you have varying levels of air sac size and need to increase the size of some, but not others, at lockdown?? I only have one incubator.